【发布时间】：2012-06-30 00:44:30
【问题描述】：
我正在使用 GridView 来显示一组用户可以选择的类别。网格的每个项目都由一个 ImageView 和一个 TextView 组成，两者都从服务器检索。当一个项目被触摸时，另一个活动被启动。
我以为一切正常，直到我注意到滚动屏幕时有些项目重复出现。每当我在网格中向下滚动然后返回时，它都会改变它的位置并被复制。但即使我触摸了混乱的项目，正确的值也会发送到下一个活动。
在 LogCat 中，任何对服务器的重复请求都会发生。事实上，我在滚动时得到了这个：
06-28 12:36:38.554: D/dalvikvm(358): GC_EXTERNAL_ALLOC freed 2061 objects / 156024 bytes in 51ms
06-28 12:36:42.915: D/dalvikvm(358): GC_FOR_MALLOC freed 6590 objects / 737528 bytes in 57ms
06-28 12:38:26.725: D/dalvikvm(358): GC_EXTERNAL_ALLOC freed 5426 objects / 468176 bytes in 71ms
06-28 12:38:26.875: D/dalvikvm(358): GC_EXTERNAL_ALLOC freed 409 objects / 17480 bytes in 68ms
看起来每次我滚动时，都会重绘...
更新：它仅在我第一次向下滚动 GridView 时重绘。在此之后，所有的元素，包括重复的元素，都会保持原位。
我的java类：
public void proccess(){
int qtdCategorias = json.length();
imagens = new Drawable[qtdCategorias];
categorias = new String[qtdCategorias];
for (int i=0; i<qtdCategorias; i++){
JSONArray c = json.optJSONArray(i);
String urlAmigavel = null;
String imagemSite = null;
String nomeCategoria = null;
try {
urlAmigavel = c.getString(6);
imagemSite = c.getString(3);
nomeCategoria = c.getString(2);
} catch (JSONException e) {
Log.e("CategoriasJogarActivity", e.toString());
e.printStackTrace();
}
categorias[i] = nomeCategoria;
imagens[i] = getImagem(urlAmigavel, imagemSite);
}
gridview = (GridView) findViewById(R.id.include3);
ImageAdapter imageAdapter = new ImageAdapter(ctx, imagens, categorias);
gridview.setAdapter(imageAdapter);
gridview.setOnItemClickListener(new OnItemClickListener() {
public void onItemClick(AdapterView<?> parent, View v,
int position, long id) {
String name = null;
String idt = null;
try {
JSONArray c = json.optJSONArray(position);
name = c.getString(2);
idt = c.getString(0);
} catch (JSONException e) {
Log.e("CategoriasJogarActivity",
"JSONException" + e.toString());
}
Intent in = new Intent(getApplicationContext(),
JogarActivity.class);
in.putExtra(TAG_NAME, name);
in.putExtra(TAG_ID, idt);
in.putExtra(TAG_PRIMEIRAPERGUNTA, true);
startActivity(in);
}
});
}
public Drawable getImagem(String urlAmigavel, String img) {
String url = "http://www.qranio.com/pergunta/" + urlAmigavel + "/"+ img;
InputStream is = null;
try {
URL urlImagem = new URL(url);
is = (InputStream) getObjeto(urlImagem);
} catch (MalformedURLException e1) {
Log.e("CategoriasJogarActivity", e1.toString());
e1.printStackTrace();
}
Drawable d = Drawable.createFromStream(is, "src");
return d;
}
private Object getObjeto(URL url) {
Object content = null;
try {
content = url.getContent();
} catch (IOException e) {
Log.e("CategoriasJogarActivity", e.toString());
e.printStackTrace();
}
return content;
}
imageAdapter 类
public class ImageAdapter extends BaseAdapter{
private Context mContext;
private final Drawable[] mThumbIds;
private final String[] mTextIds;
public ImageAdapter(Context c, Drawable[] d, String[] s) {
mContext = c;
mThumbIds = d;
mTextIds = s;
}
public int getCount() {
return mThumbIds.length;
}
public Object getItem(int position) {
return null;
}
public long getItemId(int position) {
return 0;
}
//create a new ImageView for each item referenced by the Adapter
public View getView(int position, View convertView, ViewGroup parent) {
//ImageView imageView;
View v;
if (convertView == null) { // if it's not recycled, initialize some attributes
LayoutInflater inflater = (LayoutInflater) mContext.getSystemService( Context.LAYOUT_INFLATER_SERVICE );
v = inflater.inflate(R.layout.gridview_item_layout, null);
TextView text = (TextView)v.findViewById(R.id.grid_item_text);
text.setText(mTextIds[position]);
ImageView image = (ImageView)v.findViewById(R.id.grid_item_image);
image.setImageDrawable(mThumbIds[position]);
} else {
v = (View) convertView;
}
return v;
}
}
gridview_item_layout xml
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:id="@+id/gridview_item_layout"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:orientation="vertical"
android:gravity="center_horizontal" >
<ImageView android:id="@+id/grid_item_image"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:scaleType="fitCenter"
android:minHeight="100dip"
android:minWidth="100dip"
>
</ImageView>
<TextView android:id="@+id/grid_item_text"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:text="TextView"
android:gravity="center"
android:textColor="#F9A512"
android:textStyle="bold"
android:textSize="18dp"
>
</TextView>
</LinearLayout>
网格视图 xml
<?xml version="1.0" encoding="utf-8"?>
<GridView xmlns:android="http://schemas.android.com/apk/res/android"
android:id="@+id/gridview"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:numColumns="auto_fit"
android:verticalSpacing="10dip"
android:horizontalSpacing="10dip"
android:stretchMode="columnWidth"
android:gravity="center"
android:background="#FFFFFF"
android:padding="5dip"
/>
我看到了关于同一问题的其他问题，但没有一个回答。对正在发生的事情有任何想法吗？
【问题讨论】：
-
使用 ViewHolder 是代码的好习惯
标签： android android-layout gridview drawable